Illusions are thought to make trouble for the intuition that perceptual experience is "open" to the world. Some have suggested, in response to the this trouble, that illusions differ from veridical experience in the degree to which their character is determined by their engagement with the world. An understanding of the psychology of perception reveals that this is not the case: veridical and falsidical perceptions engage the world in the same way and to the same extent. While some contemporary vision (...) scientists propose to draw the distinction between veridical experience and illusion in terms of the satisfaction or non-satisfaction of “hidden assumptions” deployed in the course of normal perceptual inference, I argue for a different approach. I contend that there are, in a sense, no illusions – illusions are as “open” as veridical experiences. Percepts lack the kinds of intentional content that would be needed for perceptual misrepresntation. My view gives a satisfying solution to a philosophical problem for disjunctivism about the good case/bad case distinction: with respect to illusions, every "bad case" of seeing an X can be equally well construed as a "good case" of seeing some Y (different from X). -/- . (shrink)

Ordinary people tend to be realists regarding perceptual experience, that is, they take perceiving the environment as a direct, unmediated, straightforward access to a mindindependent reality. Not so for (ordinary) philosophers. The empiricist influence on the philosophy of perception, in analytic philosophy at least, made the problem of perception synonymous with the view that realism is untenable. Admitting the problem (and trying to offer a view on it) is tantamount to rejecting ordinary people’s implicit realist assumptions as naive. So what (...) exactly is the problem? We can approach it via one of the central arguments against realism – the argument from hallucination. The argument is intended as a proof that in ordinary, veridical cases of perception, perceivers do not have an unmediated perceptual access to the world. There are many versions of it; I propose the following1: 1. Hallucinations that are subjectively indistinguishable from veridical perceptions are possible. 2. If two subjective states are indistinguishable, then they have a common nature. 3. The contents of hallucinations are mental images, not concrete external objects. 4. Therefore, the contents of veridical perceptions are mental images rather than concrete external objects. The key move is, I believe, from the fact that hallucinations that are subjectively indistinguishable from cases of veridical perception are possible to an alleged common element, factor, or nature, in the form of a mental state, in the two cases – that is, premise 2. Disjunctivism, at its core, can be taken as simply denying this move, and arguing that all that follows from the premise stating the possibility of hallucinations that are subjectively indistinguishable from cases veridical perception is that there is a broader category, that of “experience as of...”, which encompasses both cases.. (shrink)

We can learn much about perceptual experience by thinking about how it can mislead us. In this paper, I explore whether, and how, olfactory experience can mislead. I argue that, in the case of olfactory experience, the traditional distinction between illusion and hallucination does not apply. Integral to the traditional distinction is a notion of ‘object-failure’—the failure of an experience to present objects accurately. I argue that there are no such presented objects in olfactory experience. As a result, olfactory experience (...) can only mislead by means of a kind of property hallucination. The implications of my arguments are twofold. First, we see that accounts of representational content cannot always be based on the visual model. And, secondly, we see that we must recast the notion of nonveridicality, allowing for a notion of non-veridical experience that is disengaged from any particular object. (shrink)

The question how to account for illusion has had a prominent role in shaping theories of perception throughout the history of philosophy. Prevailing philosophical wisdom today has it that phenomena of illusion force us to choose between the following two options. First, reject altogether the early modern empiricist idea that the core subjective character of perceptual experience is to be given simply by citing the object presented in that experience. Instead we must characterize perceptual experience entirely in terms of its (...) representational content. Second, retain the early modern idea that the core subjective character of experience is simply constituted by the identity of its direct objects, but admit that these must be mind-dependent entities, distinct from the mind-independent physical objects we all know and love. I argue here that the early modern empiricists had an indispensable insight. The idea that the core subjective character of perceptual experience is to be given simply by citing the object presented in that experience is more fundamental than any appeal to perceptual content, and can account for illusion, and indeed hallucination, without resorting to the problematic postulation of any such mind-dependent objects. (shrink)

Human beings have the ability to ‘augment’ reality by superimposing mental imagery on the visually perceived scene. For example, when deciding how to arrange furniture in a new home, one might project the image of an armchair into an empty corner or the image of a painting onto a wall. The experience of noticing a constellation in the sky at night is also perceptual-imaginative amalgam: it involves both seeing the stars in the constellation and imagining the lines that connect them (...) at the same time. I here refer to such hybrid experiences – involving both a bottom-up, externally generated component and a top-down, internally generated component – as make-perceive (Briscoe 2008, 2011). My discussion in this paper has two parts. In the first part, I show that make-perceive enables human beings to solve certain problems and pursue certain projects more effectively than bottom-up perceiving or top-down visualization alone. To this end, the skillful use of projected mental imagery is surveyed in a variety of contexts, including action planning, the interpretation of static mechanical diagrams, and non-instrumental navigation. In the second part, I address the question of whether make-perceive may help to account for the “phenomenal presence” of occluded or otherwise hidden features of perceived objects. I argue that phenomenal presence is not well explained by the hypothesis that hidden features are represented using projected mental images. In defending this position, I point to important phenomenological and functional differences between the way hidden object features are represented respectively in mental imagery and amodal completion. (shrink)

Mark Changizi et al. (2008) claim that it is possible systematically to organize more than 50 kinds of illusions in a 7 × 4 matrix of 28 classes. This systematization, they further maintain, can be explained by the operation of a single visual processing latency correction mechanism that they call “perceiving the present” (PTP). This brief report raises some concerns about the way a number of illusions are classified by the proposed systematization. It also poses two general problems—one empirical and (...) one conceptual—for the PTP approach. (shrink)

Despite the recent surge in research on, and interest in, synesthesia, the mechanism underlying this condition is still unknown. Feedforward mechanisms involving overlapping receptive fields of sensory neurons as well as feedback mechanisms involving a lack of signal disinhibition have been proposed. Here I show that a broad range of studies of developmental synesthesia indicate that the mechanism underlying the phenomenon may involve reinstatement of brain activity in different sensory or cognitive streams in a way that is similar to what (...) happens during memory retrieval of semantically associated items. In the paper’s final sections I look at the relevance of synesthesia research, given the memory model, to our understanding of multisensory perception and common mapping patterns. (shrink)

This contribution explores the psychological basis of illusion and the feeling of what is real in relation to a process theory (microgenesis) of mind/brain states. The varieties of illusion and the alterations in the feeling of realness are illustrated in cases of clinical pathology, as well as in everyday life. The basis of illusion does not rest in a comparison of appearance to reality nor in the relation of image to object, since these are antecedent and consequent phases in the (...) same mental state. The study of pathological illusions and hallucinations shows that the feeling of realness in an object depends on its coherence within and across perceptual modalities. Illusion is shown to be not the taking of the phenomenal for the real, but the overlooking of the real in the phenomenal, since all things exist, i.e. are real, as categories of intrinsic relations in the unique mode of their conception. Finally, the implications of the account are discussed in relation to moral conduct, self-realization, acceptance, and the will to enjoy a world of 'brain-born' mental phenomena. (shrink)

The 'content view', in slogan form, is 'Perceptual experiences have representational content'. I explain why the content view should be reformulated to remove any reference to 'experiences'. I then argue, against Bill Brewer, Charles Travis and others, that the content view is true. One corollary of the discussion is that the content of perception is relatively thin (confined, in the visual case, to roughly the output of 'mid-level' vision). Finally, I argue (briefly) that the opponents of the content view are (...) partially vindicated, because perceptual error is due to false belief. (shrink)

Recent work on seeing-in has taken a pluralist turn. There is variety among pictures, so we should expect variety among seeing-in. Dominic Lopes’s taxonomy of seeing-in is arguably the most thorough that is currently available. Lopes identifies five varieties of seeing-in. In this paper I identify a sixth: pseudo-actualism. This paper improves our current best taxonomy of seeing-in.

The subjective character of a given experience leaves open the question of its precise status. If it looks to a subject K as if there is an object of a kind F in front of him, the experience he is having could be veridical, or hallucinatory. Advocates of the Causal Theory of perception (whom I shall call.

One central fact about hallucinations is that they may be subjectively indistinguishable from perceptions. Indeed, it has been argued by M. G. F. Martin and others that the hallucinatory experiences concerned cannot — and need not — be characterised in any more positive general terms. This epistemic conception of hallucinations has been advocated as the best choice for proponents of experiential (or ‘na¨ıve realist’) disjunctivism — the view that perceptions and hallucinations differ essentially in their introspectible subjective characters. In this (...) chapater, I aim to formulate and defend an intentional alternative to experiential disjunctivism called experiential intentionalism. This view does not only enjoy some advantages over its rival, but also can hold on to the epistemic conception of perception-like hallucinations. First of all, I try to spell out in a bit more detail in which sense hallucinations may be subjectively indistinguishable from perceptions, and why this leads us to erroneously judge them to be perceptions (cf. sections I–III and VIII). Then, I raise three challenges each for experiential disjunctivism and its orthodox intentionalist counterparts (cf. sections IV and V), notably in respect of the need to explicate why a perception-like hallucination still makes the same judgements reasonable from the subject’s perspective as the corresponding perceptions. And, finally, I propose my alternative both to experiential disjunctivism and to orthodox intentionalism. Experiential intentionalism takes perceptions and perception-like hallucinations to share a common character partly to be spelled out in intentional — and, hence, normative — terms (cf. sections VI and VII). The central thought is that the hallucinations concerned are intentionally — and erroneously — presented to us as perceptual relations to the world. I aim to show that the resulting view can meet all six challenges (cf. sections VI–VIII). I end.. (shrink)

Finding disjunctivist versions of direct realism unexplanatory, Mark Johnston [(2004). Philosophical Studies, 120, 113–183] offers a non-disjunctive version of direct realism in its place and gives a defense of this view from the problem of hallucination. I will attempt to clarify the view that he presents and then argue that, once clarified, it either does not escape the problem of hallucination or does not look much like direct realism.

Firth argues that austin's criticisms of the argument from illusion do not destroy the argument. We can reformulate it in two ways so that it succeeds as a method of ostensibly defining terms denoting the sensory constituent of perceptual experience. One way maintains the act-Object distinction of the cartesian tradition and the other uses the language of "looks." (staff).

This book provides the first full-length treatment of disjunctivism about visual experiences in the service of defending a naive realist theory of veridical visual perception. It includes detailed theories of hallucination and illusion that show how such states can be indistinguishable from veridical experiences without sharing any common character.

The present investigation concerns Reid’s explanation of how objects (be they real or nonexistent) are conceived. This paper shows that there is a deep-rooted tension in Reid’s understanding of conception: although the type of conception employed in perception is closely related to the one employed in imagination, three fundamental features distinguish perceptual conception (as the former will be referred to throughout this paper) from imaginative conception (as the latter will be called henceforth). These features would have been ascribed by Reid (...) himself to conception as involved in perception, but not to conception as involved in imagination. He should have recognized them as marking the former as a different kind from the latter, and he should not have hastily lumped perceptual and imaginative conceptions together. (shrink)

Recent debates between representational and relational theories of perceptual experience sometimes fail to clarify in what respect the two views differ. In this essay, I explain that the relational view rejects two related claims endorsed by most representationalists: the claim that perceptual experiences can be erroneous, and the claim that having the same representational content is what explains the indiscriminability of veridical perceptions and phenomenally matching illusions or hallucinations. I then show how the relational view can claim that errors associated (...) with perception should be explained in terms of false judgments, and develop a theory of illusions based on the idea that appearances are properties of objects in the surrounding environment. I provide an account of why appearances are sometimes misleading, and conclude by showing how the availability of this view undermines one of the most common ways of motivating representationalist theories of perception. (shrink)

In Remarks on the philosophy of psychology Wittgenstein uses ambiguous illusions to investigate the problematic relation of perception and interpretation. I use this problem as a starting point for developing a conceptual framework capable of expressing problems associated with visual perception in a precise manner. I do this by discerning between subjective and objective meaning of the term “to see” and by specifying the beliefs which are to be ascribed to the observer when we assert that she sees a given (...) object. The framework (detailed in section 2) is then used to analyze the case of the duck/rabbit illusion. It shows that ambiguous illusions present us with a specific skeptical challenge but that the challenge can be overcome by empirical sciences. Along the way I explicate some of the common notions associated with perception (“to look at”, “to have an impression of…”, "to react as if one had an impression of..”, “to convince oneself that what one sees is…”). (shrink)

Recent neural models clarify many properties of mental imagery as part of the process whereby bottom-up visual information is influenced by top-down expectations, and how these expectations control visual attention. Volitional signals can transform modulatory top-down signals into supra-threshold imagery. Visual hallucinations can occur when the normal control of these volitional signals is lost.

Philosophers of mind have recently sought to establish a theoret- ical use for nonconceptual content. Although there is disagreement about what nonconceptual content is supposed to be, this much is clear. A state with nonconceptual content is mental. Hence, while one may deny that refrigerators and messy rooms have conceptual capacities, their states, as physical and not mental, do not have nonconceptual content. A state with nonconceptual content is also intentional, which is to say that it represents a feature of (...) the world for a subject. It may be tempting to think of qualitative states as having nonconceptual content since they can be experienced by indi- viduals independently of their possession of the requisite concepts, e.g. someone could experience pains, itches or tingles without possessing the concept pain, itch or tingle. But on such a view, one would have to assume that qualitative states are representational since mental states cannot be candidates for nonconceptuality unless they have intentional properties.2. (shrink)

Inspired by the writings of J. M. Hinton (1967a, 1967b, 1973), but ushered into the mainstream by Paul Snowdon (1980–1, 1990–1), John McDowell (1982, 1986), and M. G. F. Martin (2002, 2004, 2006), disjunctivism is currently discussed, advocated, and opposed in the philosophy of perception, the theory of knowledge, the theory of practical reason, and the philosophy of action. But what is disjunctivism?

We begin with a theory of the structure of sensory consciousness; a target phenomenon of 'presentation' can be clearly located within this structure. We then defend the rational-psychological necessity of presentation. We conclude with discussion of these philosophical challenges to the possibility of presentation. One crucial aspect of the discussion is recognition of the <cite>nonobjectivity</cite> of consciousness (a technical appendix explains what I mean by that). The other is a full-faced stare at the limitations of rational psychology: much of the (...) dialectic in the philosophy of perception pertains to matters beyond the limits of coherence---a breakwater against which philosophy crashes, and rolls back. (shrink)

Although it has been something of a fetish for philosophers to distinguish between hallucination and illusion, the enduring problems for philosophy of perception that both phenomena present are not essentially different. Hallucination, in its pure philosophical form, is just another example of the philosopher’s penchant for considering extreme and extremely idealized cases in order to understand the ordinary. The problem that has driven much philosophical thinking about perception is the problem of how to reconcile our evident direct perceptual contact with (...) objects and properties with the equally evident fact that there is no phenomenological signal separating error and truth. “The obscure object of hallucination” offers a subtle and plausible solution to this problem and one that solves the problem generally, not just in the special case of hallucination. Johnston’s objective is to offer a theory of perception that meets two constraints: (1) that it provide an explanation of the possibility of delusive and veridical sensings that are indistinguishable from the ﬁrst-person perspective and (2) that it count as form of direct realism where this is taken to involve acquaintance with the objects of perception. Johnston uses the ﬁrst constraint to rule out disjunctivism. The second constraint is used to rule out conjunctivism, which as Johnston uses the term, includes most of the widely adopted philosophical theories of perception. Johnston also develops his own sophisticated and interesting theory of perception. In what follows, I will discuss the relation of Johnston’s theory to conjunctivism, examine one of his anti-conjunctivist arguments and ﬁnally compare Johnston’s theory with some other versions of direct realism. These topics constitute a very incomplete selection of the important issues discussed in this rich and interesting paper. I will also not disagree, in any fundamental way, with any of the central theses of Johnston’s discussion.. (shrink)

In apparent motion experiments, participants are presented with what is in fact a succession of two brief stationary stimuli at two different locations, but they report an impression of movement. Philosophers have recently debated whether apparent motion provides evidence in favour of a particular account of the nature of temporal experience. I argue that the existing discussion in this area is premised on a mistaken view of the phenomenology of apparent motion and, as a result, the space of possible philosophical (...) positions has not yet been fully explored. In particular, I argue that the existence of apparent motion is compatible with an account of the nature of temporal experience that involves a version of direct realism. In doing so, I also argue against two other claims often made about apparent motion, viz. that apparent motion is the psychological phenomenon that underlies motion experience in the cinema, and that apparent motion is subjectively indistinguishable from real motion. (shrink)

Like dreaming, hallucination has been a formative trope for modern philosophy. The vivid, often tragic, breakdown in the mind’s apparent capacity to disclose reality has long served to support a paradoxical philosophical picture of sensory experience. This picture, which of late has shaped the paradigmatic empirical understanding the senses, displays sensory acts as already complete without the external world; complete in that the direct objects even of veridical sensory acts do not transcend what we could anyway hallucinate. Hallucination is thus (...) the mother of Representationalism, which insists that it is mental intermediaries that make other.. (shrink)

Michael Martin aims to affirm a certain pattern of first-person thinking by advocating disjunctivism, a theory of perceptual experience which combines naive realism with the epistemic conception of hallucination. In this paper I argue that we can affirm the pattern of thinking in question without the epistemic conception of hallucination. The first part of my paper explains the link that Martin draws between the first-person thinking and the epistemic conception of hallucination. The second part of my paper explains how we (...) can achieve Martin’s ambition without Martin’s theory. One resource that I enlist for this purpose is a naive-realist friendly conception of first-person access to experience. The metaphysical theory that I enlist is a form of naive realism that endorses an intentionalist or representationalist “common-factor” approach to veridical and hallucinatory experience. The third part of my paper briefly develops this theory. (shrink)

The paper's first four sections give a taxonomy and criticism of three classes of objections to the argument from illusion. the last section raises the question whether its main premise does not misclassify perceptual accusatives (e.g. 'sensation of bentness') as individuatives that imply the existence of, say, bent particulars.